The long term goal of this project is to control or prevent chlamydia TWAR infection. A major aim of these studies is to describe the epidemiology of TWAR infection. This project will contribute to that goal through seroepidemiologic studies utilizing the micrimmunofluorescence test with a number of serum banks related to respiratory infections. Three of these banks cover 12 to 20 years beginning as early as 1964 and will be particularly useful in determining the periodicity and seasonality of TWAR infection. Several include family groups and will provide informtion on intrafamily transmission and infectiousness of TWAR. Families that have been under long term observation may provide information on reinfection. Specialized serum banks will provide information on TWAR as a cause of hospitalized pneumonia, and the role of TWAR infection in chronic obstructive pulmonary disease and cystic fibrosis. The seroepidemiologic studies will contribute to knowledge on the general epidemiology of TWAR, including its occurrence by age, sex and occupation. They will also provide information on clinical syndromes associated with TWAR infection, including asymptomatic infection. Efforts will be made to improve laboratory diagnostic methods and growth of the TWAR organism. Experiments will be directed at more efficient isolation and growth methods, both with a variety of cell cultures and embryonated chicken eggs. Studies of direct demonstration of TWAR in patient specimens will include fluroescent antibody staining with monoclonal antibody, antigen capture assays and DNA probes. In an effort to simplify serology, the sensitivity and specificity of the ELISA test with TWAR recombinant DNA antigens will be evaluated. Ultrastructural studies of the TWAR organism will concentrate on the unique cell wall of the elementary bodies and the "minibodies" found in elementary bodies. Definitive classification of the TWAR organisms among the Chlamydia will be assisted by studies of DNA homology and nutritional requirements, of TWAR and other Chlamydia.